ABSTRACT
Thus far two related themes, the development of church structures and the interplay of the church and political life, have held centre stage. From a historian's point of view, those topics are very important because creative tension among rival institutions shaped both the western church and western society. But most medieval Christians were only dimly aware of those .important developments. The fact that the Christian church was an economic power, a political force and a sociological phenomenon can obscure the obvious point that to contemporaries it was the embodiment of a living religion which explained the universe to them and offered them salvation. The church's position in society was based on the belief held by the overwhelming majority of western Europeans that it literally held the keys to the kingdom of heaven.
